Real life is much darker.

The ones who stop moving for a split second get eaten by the rest.

The added protein makes them stronger, and the strongest keep reproducing. So the longer the swarm lasts, the worse it gets

Locust swarms are basically just a herd of cannibal zombies where the ones in front are being chased by the ones behind them. So they eat everything to keep their strength up and everytime they hit a field of crops they regain their numbers.